The Emergency Medicine entrance at the George Washington University Hospital on Dec. 21. (Craig Hudson for The Washington Post)

A winter surge in coronavirus cases and an uptick in acutely sick patients is overwhelming hospitals across the region and nation, leading to long wait times that emergency medicine experts and first responders say threaten patient safety.

First responders monitoring Maryland’s hospitals for signs they might need to divert patients from busy emergency rooms saw their dashboards light up in recent weeks. When inpatient hospital beds fill up, emergency departments have no place to send patients who must be admitted to the main hospital for further care, leaving them stuck as others languish in waiting rooms.